How the Aztec Empire Rose and Fell in Under Two Centuries
By the BrainSnail editorial team. How these articles are written and checked, and how to tell us when one is wrong.
In 1325 a wandering people settled on a marshy island in a lake in central Mexico because, their priests said, they had seen an eagle perched on a cactus there. Two centuries later their city, Tenochtitlan, had perhaps 200,000 inhabitants, more than any city in Spain, and ruled over several million people through a web of alliances and tribute. Two years after the Spanish arrived, it was rubble. The speed of both the rise and the fall is the thing to explain.
Latecomers in an old world
The people we call Aztecs called themselves Mexica, and they arrived late in a region that had seen cities for two thousand years. Teotihuacan, whose pyramids still stand north of Mexico City, had held 100,000 people before 600 CE; the Toltecs had followed; by the 1300s the Valley of Mexico was a patchwork of city-states around a system of lakes, all speaking Nahuatl and sharing gods, calendars and a taste for warfare. The Mexica were poor migrants from the north who hired themselves out as mercenaries and were tolerated on land nobody else wanted.
The island turned out to be an asset. It was defensible, the lake gave fish and waterfowl, and the Mexica built chinampas, raised fields of mud and vegetation piled up in the shallows, that produced several crops a year and eventually fed a vast city. Causeways linked the island to the shore, and an aqueduct brought fresh water from the springs at Chapultepec.
The Triple Alliance
In 1428 the Mexica joined two neighbouring cities, Texcoco and Tlacopan, to overthrow the dominant power in the valley, and the Triple Alliance they formed is what the word empire really refers to. Over the next ninety years it conquered outward in every direction, reaching both coasts, and the Mexica ruler became the senior partner. The empire did not govern its conquests directly. Defeated cities kept their rulers and their gods and paid tribute, cotton cloth, maize, cacao, feathers, gold, jade, warriors, and the tribute lists that survive show the flow of wealth into Tenochtitlan.
Warfare was constant and had a religious dimension. The gods, the Mexica believed, required human blood to keep the sun moving, and the flower wars, ritualised battles fought with neighbouring states, supplied captives for sacrifice at the Great Temple at the city's heart. The scale is debated; the fact is not. It also meant the empire never lacked enemies, and the cities it had defeated but not absorbed, above all Tlaxcala, which it had never conquered, remembered.
A city on the water
The Spaniards who first saw Tenochtitlan in 1519 compared it to Venice and to the enchanted cities in the romances they had read. Bernal Diaz, a soldier who wrote his memoir decades later, said some of the men asked whether they were dreaming. The city had straight canals and streets, a great market at Tlatelolco that a Spaniard estimated held 60,000 people a day, palaces, zoos, botanical gardens, schools for the children of nobles and commoners alike, and a sanitation system that put European cities to shame. Its rulers were literate, its astronomers kept an accurate calendar, and its poets composed verse that survives.
Two years
Hernan Cortes landed on the Gulf coast in 1519 with about five hundred men, sixteen horses and a few cannon. He could not have taken the empire with that, and he did not. What he had was the empire's enemies. The Tlaxcalans, after fighting him, allied with him and supplied tens of thousands of warriors; so did other subject cities glad to see the Mexica humbled. The emperor Moctezuma admitted the Spaniards to the city, was taken hostage, and died in the fighting that followed in 1520, when the Spaniards were driven out with heavy losses on the night the Spaniards called the sorrowful night.
Cortes returned in 1521 with his allies, built boats to control the lake, cut the causeways and the aqueduct, and besieged the city for three months. By then smallpox, brought by a Spanish soldier the previous year, had swept through a population with no immunity and killed a large part of it, including the new emperor. Tenochtitlan fell on 13 August 1521 after house-to-house fighting that left it in ruins. The causes, in rough order of weight:
- •Tens of thousands of indigenous allies who wanted the Mexica gone
- •Smallpox, which killed perhaps a third of the population before the siege
- •Steel, horses, cannon and ships on the lake, decisive in the final assault
- •An empire of tribute rather than integration, with no loyalty to draw on
- •A political crisis at the top after Moctezuma's death
What survived
The Spanish built Mexico City on the ruins, and the Great Temple lies under its central square, excavated since 1978. Nahuatl is still spoken by more than a million people. The chinampas survive at Xochimilco, still farmed. The foods the Mexica cultivated, maize, beans, chillies, tomatoes, cacao, avocados and vanilla, went on to change the diet of the world. And the eagle on the cactus that the priests saw in 1325 is on the flag of Mexico.
Did the Mexica really think Cortes was a god
One of the most repeated stories about the conquest is that Moctezuma believed Cortes was the returning god Quetzalcoatl, and so welcomed him instead of fighting. Many historians now doubt it. The story does not appear in the letters Cortes wrote to the Spanish king at the time, which would surely have mentioned so useful a belief. It surfaces in accounts written decades later, after the conquest, when both Spanish friars and some Nahua writers had reasons to explain the catastrophe as fate or prophecy rather than as the result of alliances, disease and war.
That points to the bigger question of how anything about the Mexica is known. Much comes from sources produced after 1521: the Codex Mendoza, made for Spanish officials with pictures of tribute and daily life, and the Florentine Codex, a huge encyclopedia compiled by the friar Bernardino de Sahagun with Nahua scholars and elders, written in Nahuatl and Spanish. These are priceless but were shaped by the conquerors' questions and the survivors' memories. Archaeology, especially excavation of the Great Temple, provides an independent check, and historians weigh all of these against one another rather than trusting any single account.
The Sun Stone is not a calendar
The most famous Mexica object, the great carved disc usually called the Aztec calendar, is not really a calendar. Known as the Sun Stone, it was found in December 1790 when workers were levelling Mexico City's main square, and it measures about 3.6 metres across and weighs roughly 24 tonnes. It was never a device for reckoning dates. It is a monumental sculpture of the Mexica cosmos: around a central face sit four panels representing the four earlier ages, or suns, that the Mexica believed had each been destroyed, and around them runs a ring of the twenty day signs.
The Mexica did keep careful track of time, using two cycles that ran side by side. One was a solar year of 365 days, eighteen months of twenty days plus five extra days regarded as unlucky. The other was a ritual count of 260 days, made by pairing the numbers one to thirteen with the twenty day signs. A given combination of both cycles came round again only every 52 years, and the end of each such cycle was marked by the New Fire ceremony, when fires were put out across the valley and relit from a single flame kindled on a hilltop.
The goddess under the street
In February 1978, workers from Mexico City's electricity company were digging beneath a street near the cathedral when they struck a huge carved stone. It was a disc more than three metres across showing Coyolxauhqui, a goddess dismembered by her brother Huitzilopochtli, the Mexica god of the sun and war. In the myth, Huitzilopochtli was born fully armed on the mountain of Coatepec and killed his sister, who had led an attack on their mother, hurling her body down the slope, where it broke apart. The find led the government to clear several blocks of the old centre and excavate the Great Temple properly.
The excavation showed that the temple had been enlarged again and again, each new pyramid built over the old one like the layers of an onion, so archaeologists could study several earlier versions nested inside. On its summit stood two shrines, one to Huitzilopochtli and one to the rain god Tlaloc, joining war and farming at the heart of the city. The pyramid stood for the mountain of the myth itself. The Coyolxauhqui stone lay at the foot of Huitzilopochtli's stairway, so the bodies of sacrificed captives cast down the steps re-enacted the goddess's fall, a rare case where archaeology shows exactly how a myth was staged in stone.
The takeaway
The Mexica rose from migrants on a marsh to rulers of central Mexico in two centuries through the Triple Alliance and a system of tribute enforced by constant war, and built in Tenochtitlan one of the great cities of the world. The same system left them surrounded by enemies, and when the Spanish arrived with steel, smallpox and, above all, tens of thousands of indigenous allies, the empire was gone in two years.